At 03:04 PM 12/11/2007, you wrote:
>You have a pretty good handle on the issues.  The gain set resistor is
>of interest if you ever need to replace the sensor and don't want to
>have to re-calibrate the system.  ICSensors says using it will give less
>than 1% variation in gain from unit to unit.  I used to use lots of
>those sensors and took advantage of the gain resistor to eliminate a
>gain trimpot for the system.  So you can use an integrated solution
>without discrete resistors but may have to re-cal at some point if you do.
>
>Probably, a tougher decision for you is going to be the output swing.
>If you need to have an output go to zero volts, you will have to either
>create a negative rail or offset the output to something like 1 volt or
>whatever works for your system.  This can be derived from the voltage
>reference you are using to set the excitation current.
>
>Good luck!

Another possibility would be to use a dual precision op-amp (similar to the
datasheet circuit) and use two ADC inputs to read the difference. That would
allow a zero reading, or even a negative reading. Of course that makes more
sense with differential pressure, some sense with gauge pressure, and less
with absolute pressure unless you're measuring a vacuum.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com



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